1. Field
This invention is directed to an apparatus for burning sulfur to sulfur dioxide, which sulfur dioxide is associated with a multi-channel gas valve associated with multiple gas sources to selectively blended them into water with a combination mixer/aerator to aerate water in one monde, admix sulfur dioxide with water to form sulfurous acid in another mode, and stir and mix water without gases, in another mode.
2. State of the Art
Various sulfur burning sulfur dioxide generators are known and used for various purposes, such as that described in Harmon, U.S. Pat. No. 3,226,201 issued Dec. 28, 1965 entitled “Apparatus for Treating Irrigation Water” burning sulfur to produce sulfur dioxide for injection into irrigation water for pH adjustment. Harmon, U.S. Pat. No. 3,337,989 issued Aug. 29, 1967 entitled “Process of Treating Soil Containing Carbonates” was directed toward burning sulfur to produce sulfur dioxide for injection into water to produce sulfurous acid for soil treatment. Mattson, U.S. Pat. No. 3,627,134 issued Dec. 14, 1971 entitled “Water Treatment Device” uses a two-zoned tank to produce sulfur dioxide for injection into water to produce a concentrated solution of sulfurous acid, which is then used to acidify irrigation water. Collins, U.S. Pat. No. 3,907,510 issued Sep. 23, 1975 entitled “System for Burning Sulfur and Absorbing Sulfur Dioxide in Water” burns sulfur to produce sulfur dioxide, which rises through packing through a countercurrent stream of water to produce sulfurous acid for agricultural applications. Collins et al., U.S. Pat. No. 4,039,289 issued Aug. 2, 1977 entitled “Sulphur-Burning and Gaseous Products Absorption System and Components Therefore” burns sulfur to produce sulfur dioxide, which is directed to pass through an absorption tower with pre-cooling means to further improve absorption tower efficiency via temperature regulation sensors increasing the flow of water through the countercurrent tower.
Lewis et al., U.S. Pat. No. 4,966,757 issued Oct. 30, 1990 entitled “Sulfur Dioxide Generator” employs dual burn chambers to produce sulfur dioxide directed through a countercurrent absorption tower under negative pressure. Forbush et al., U.S. Pat. No. 4,526,771 issued Jul. 2, 1985 entitled “Sulfurous Acid Generator” employs dual burn chambers to produce sulfur dioxide, which is directed through an absorption tower to produce sulfurous acid. These devices are limited in the maximum burning rate of sulfur per hour to approximately 7 pounds of sulfur per hour per square foot of burning surface. The Sulfurous Acid Generator of U.S. Pat. No. 4,526,771 utilizes a positive pressure air feed system which significantly increased the sulfur burn rate and efficiency, but did not provide sufficient ability to provide varying strengths of acids required by farmers for differing agricultural applications. Also, because of the positive air pressure oxygen feed system, this '771 sulfurous acid generator was subject to sulfur dioxide leaks through breaks in seals, and machine welds which could jeopardize the operator. The heat produced from burning sulfur was not recaptured, but dissipated into the atmosphere.
Jackson, U.S. Pat. No. 6,689,326 issued Feb. 10, 2004 entitled “Method and Apparatus for Introducing Sulphur Dioxide into Aqueous Solutions” is a sulfurous acid generator, which injects sulfur dioxide gas into a pressurized fluid line of aqueous solution to form sulfurous acid, without employing a countercurrent absorption tower.
Cited for general interest is Gillett, U.S. Pat. No. 1,638,992 issued Mar. 28, 1925 entitled “Sulphur Burner”, which burns sulfur to generate heat to be used to produce steam. Zeisberg, U.S. Pat. No. 1,545,381 issued Jul. 7, 1925 entitled “Burning Sulphur and Recovery of Heat Generated” is another device for burning sulfur to generate and recover heat, while producing sulfur dioxide for process use. Chickering, U.S. Pat. No. 1,450,677 issued Apr. 3, 1923 entitled “Sulphur Burner” is another device for burning sulfur high in ash content to produce sulfur dioxide. Schendel, U.S. Pat. No. 5,204,082 issued Apr. 20, 1993 entitled “Sulfur Dioxide Generation by Submerged Combustion and Reduced Thermal Cycling by Use of a Hot Recycle of Sulfur” is a method producing high purity sulfur dioxide by submerged combustion. The Sulfur is combusted in a first liquid pool with an oxygen containing gas and the vapor effluent is removed and cooled in a first cooling zone at a temperature above 600 degrees F. to separate the liquid sulfur from the vapor for re-burning. Mcllroy et al, U.S. Pat. No. 3,723,068 issued Mar. 27, 1973 discloses an apparatus for the preparation of sulfur dioxide whereby the sulfur is burned within a cyclone furnace supplied with a closely controlled amount of excess air to minimize sulfur trioxide formation. The combustion product gases are passed through a water spray tower for cooling and to remove any sulfur trioxide present. Smith, U.S. Pat. No. 6,464,885 issued Oct. 15, 2002 entitled “Water Treatment Systems” discloses a system for processing water by adding an additive to a stream of pressured fluid containing chlorine to which a supply of dechlorinating additive (such as sulfur dioxide) is injected for chlorine removal.
The present invention provides an improved sulfur dioxide generator in combination with an aerator/mixer with multi-functionality, providing precision controlled fine bubble aeration and impeller mixing capable of drawing in additional gases such as sulfur dioxide to provide the varying gas concentrations required for water treatment of open ponds and enclosed tanks, as more fully described below.